“Expect the unexpected” is the subtitle of this autobiographical manifesto originally published in German in 2014. The admonition certainly seems justified on p. 56, where Kent Nagano criticizes the educational assessment tests administered by the Organisation for Economic Co-Operation and Development; on p. 85, where we are warned, courtesy of the liberal billionaire George Soros, of the “excesses on unfettered capitalism”; and on p. 159, where the subject is the role of the hormone prolactin in regulating the paradoxically positive feelings humans experience when listening to sad music.

Part memoir and part polemic, this is emphatically not a sequence of backstage anecdotes and heartwarming vignettes, although we do meet a few celebrities. Some readers will be surprised by the hot topics — the influence of period practice, the swelling ranks of female conductors, the infiltration of the opera stage by postmodern madness, the MeToo movement, the esthetics of minimalism — that go unmentioned. Yet the book is engaging despite its detours, and vigorously argued on every page. Above all it is passionate in its advocacy of classical music as an eternal pathway to individual spiritual awareness and a tonic for what ails the modern age.

And classical music is distinctly the topic Nagano wishes to discuss. While this American (who self-identifies as such notwithstanding a career that keeps him mostly in Canada and Europe) apparently relates to the progressive side of various political issues — Chapter 3 begins with applause for the anti-establishment writings of the late French provocateur Stéphane Hessel — he is high Tory on the matter of the potential reach of great art and adheres tenaciously to the belief that all should have access to it. Not for Nagano the post-structuralist notion that Schoenberg and the Cirque du Soleil are of equal esthetic value. While he confesses admiration for John Lennon’s Imagine as “high art in the field of pop music,” he is firmly on the classical side of the divide. Even his famous enthusiasm for Frank Zappa is an expression not of an urge to play nice with rockers but a real admiration for the “classical” complexity of this composer’s little-understood orchestral scores.

If the outlook is elitist, it is elitist in the most democratic sense. The new availability of music through streaming and YouTube represents a golden opportunity to revive the ideal of making Beethoven the popular hero he was 200 years ago in Vienna. “Let’s transform ‘the crisis of classical music’ into ‘classical music for a time of crisis,’ ” Nagano writes. “Maybe this period of upheaval is its biggest opportunity.”

There are, of course, obstacles. Political and societal leaders are ignorant of both the arts and their role in maintaining civil society. The absence of the arts from early education (and the aforementioned assessment tests) is a particularly dangerous situation. Nagano is skeptical of the belief — clung to desperately by this writer, among others — that adults will constantly replenish the classical ranks in middle age as they find more time for contemplative listening. Early exposure is crucial.

He thinks so because he was himself exposed to music in Morro Bay, a coastal California community that was substantially agricultural. Expected by his university-educated parents (who were farmers by necessity) to practise piano, Nagano was electrified by Georgian-born Wachtang Korisheli, an itinerant music teacher who taught privately and, through his work on the school orchestra, “metamorphosed Morro Bay into a village of sound.” Multiple ethnicities found common ground.

After this description of his upbringing, we proceed promptly to Bach, the composer Nagano is most likely to play or peruse in his free time. “Everything is interconnected,” he writes about the seminal master without whom the subsequent course of music is difficult to imagine. “Entertainment and profundity, pedagogy and creativity, logic and feeling.”

There are chapters devoted to others in his personal pantheon: Schoenberg, who was gripped by a revolutionary impulse whose results listeners still find troubling; Beethoven, whose apparently abstract works can be heard both pictorially and as a portent of the Industrial Revolution; Bruckner, whose awe-inspiring command of harmonic motion, dynamic contrast and thematic architecture creates “an expanding universe that continually nourishes an intimation of its infinite magnitude”; Charles Ives, whose chaotic rhetoric mirrors the American experience; and Leonard Bernstein, whose status as a media star has obscured the value of his later compositions (and who spoke personally to Nagano about his ill-starred opera A Quiet Place).

There is naturally a portrait of Olivier Messiaen, with whom Nagano lived as a musical assistant in Paris (without, interestingly, ever setting foot in his upstairs studio). Famously inspired by birdsong, this devoutly Catholic organist/ornithologist sought to “lend an acoustic shape to timeless truths.” Nagano, raised a Presbyterian, makes it clear in this section that he remains a believer.

Not that his convictions preclude an interest in the neurochemistry of music perception, which he discusses at length with the psychologist Daniel Levitin in a situation that essentially casts Nagano as a journalist conducting an interview. Late in the book there are like encounters with the amusingly off-the-cuff German Chancellor Helmut Schmidt (who compared Bach’s well-tempered tuning to the compromise required by democratic politics); Governor General Julie Payette (who recounts listening to Handel as wake-up music in space); filmmaker-turned-opera-director William Friedkin (whose cinema students have never heard of Orson Welles); and Canadian novelist Yann Martel (who wishes people would stop obsessing about money).

Fear not: there are several pages recounting the past and present of the OSM, including a discussion of the “Les Glorieux” collaboration with the Montreal Canadiens and other high-profile projects. Adding more Austro-German repertoire to the Franco-Russian playlist was a priority. Nagano describes the contemporary sound of the OSM as “Québécois: brilliant, very warm, lean, elegant, not very American, but not purely European, either.” At any rate, the tonal differences of high-level orchestras are “only nuances.” Most important was outreach to a younger audience.

The translation by Hans-Christian Oeser is idiomatic. The few editing slips (Bruckner’s so-called Symphony No. 0 is said to be in B Major rather than D Minor) are not game-changers, although one might expect Nagano himself to have caught the misrepresentation of his OSM title (music director, not chief conductor). Inge Kloepfer, a journalist working in Berlin, co-authored the original text, which has clearly been modified to make room for references to a certain American president who could hardly be absent from a jeremiad on the dilemma that the United States finds itself in. Nevertheless, Nagano’s final words are hopeful. After all, he loves music.